Dash-pot.



PATENTED SEPT. 251906,

P. E. LA MMERT.

DASH POT. APPLICATION FILED DEC. 6. 1904.

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PATENTED SEPT. 25, 1906.

F. E. LAMMERT. DASH POT. APPLICATION FILED DEC. 6, 1904.

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FERDlNAND ERNST- LAMMERT, OF CHICAGO, lLLlNOlS.

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Specificaton of Letters Patent.

Patented Sept. 25, 1906.

Application filed December 6,1904. Serial No- 236,777.

To all whmn it m/ay concern:

Be it known that I FaRDrNANn Ennsr LAMMERT, a citizen of the United States of America, and a resident of Chicago, county of Cook, State of Illinois, have invented certain new and useful Improvements in Dash- ?ots, of which the following is a specification.

The object of this invention is to produce a dash-pot that shall be free from the hammerblow of ordinary devices of this class.

in the accompanying drawings, Figure 1 shows my device invertical axial section, 'a certain plunger being in depressed position. Fig. 2 is a section on the line 2 2, Fig. 1. Fig. 3 is a view similar to Fig. but showing a ig. 4'is a section or, the lined 4, Fig. 3. Fig. 5 is a view similar to Fig. 3, showing the plunger in raised position. Fig. 6 is a section like Fig. 1, but showing the lunge'r raised. Fig. 7 is a partial view ana ogous to Fig. 1, showing a modified construction.

in. this apparatus oil or other fluid contained in a suitable cylinder or casing is trapped in the lower part of the cylinder by a descending plunger, but is permitted to escape gradually, as the descent of the plunger continues, in a suitable cavity within the easing, and the parts are so arranged that the cross-sectional area of the escaping body is gradually decreased until at the last instant escape is wholly cut off. When the plun er again ascends, the iluid reenters the space e-- low the plunger and the operation is repeated indefinitely.

1n the several figures of the drawings, 2

represents a dash-pot cylinder in which works a plunger 3, connected by a rod 4 to the working parts of an engine or the like. At one side of the cylinder is a chamber 5, communicatin with the c linder and upwardly closed l a chamber, itselfupwardly closed by a screwrecess 11 and pin *7. In the upper portion of the inner wal of the cylinder is an annular recess 8, communicatin with the open air by a passage 9 and wit the check-valve chamber bv a passage 10. The lower portion of the eviinder is provided with an analogous annular at a point still lower with an other like recess 12, these two recesses being separated by an intact portion 13 of the cylinder-wall, so that the closely-fitting plunger may when depressed leave no' communication between the two recesses. The plunger has in its lower end a downwardly-open rey a check-Va vs 6, working In E l l cess l5 andabove this recess an interior cavity l4, separated from said recess by awall 16, which is centrally perforated to permit the entrance of a conical or bottle shaped block 17 which is fixed to the bottom of the cylinder. The chamber 14 connnunicates with the atmosphere by a pipe 18, closed by a check-valve 1!), which permits fluid to pass outward, but not inward. Passages 20 lead outward from the cavity 14 through the walls of the plunger, and like passages 21 lead outward in lilie manner from the cavity 15, these latter passages being in dill'erent horizontal planes, as shown. The block 17 is provided with a passage 22, which extends downward from its upper end and then laterally outward at apoint such that the opening is reached by the partition between the cavities 14 15 only when the plunger reaches a point near its lower limit of movement. In order that the fluid may pass out through the holes 20 when the plunger is raised, the interior of the cyliuder'is provided with vertical grooves 25, registering with the openings 20.

In preparing the dash pot for use all its cavi ties, including the chamber 5, are filled with oil or the like, and the plunger being then pressed down in the cylinder the surplus oil and air are forced out through the checkvalves6 and 19,the oil which escapes through the check-valve 6 passing through the passages 10 8 9. Some portion evidently remains in the recess 8 and serves as a packing and. lubricant ior the plunger as the latter reciprocates in the cylinder.

Under normal conditions the oil stands at about the level of the .seat ofthe valve 6 when the plunger is down, and preferably there is no air in the cavity 14 of the plunger. When the depressed plunger is lifted, the atmospheric pressure mustv be overcome, a vacuum being created below the plunger; but in this vacuum the oil will flow downward under the force of gravity and keep the lower ortions of the internal space filled. The Oil eing thus in the lower part of the cylinder, the plunger as it descends, traps it in the s ace 12 and compels it to escape upwar tlirough the opening for the block 17 and the passages .20, '21, and 22 into the cavity 14 and recess 11. As the plunger continues its descent, these passages are gradually cut oil one after the other, ,andthus the plunger comes to rest withoutshoclq, its force being expended in forcing the oil out of the lower part of the cylinder through passages which creased resistance.

time when the lower surface of the plunger is not in contact with the oil below it, and hence it can never move down to meet the oil with a hammer-blow.

In theform illustrated in Figs. 3, 4, and 5 the bottle-like block is omitted and. wall 16 is not provided with the corresponding openin Fig. 7 the projection 17 is replaced by a cylindrical tube 26, provided with numerous 2o lateral perforations 27, the apparatus being in other respects unchanged.

What I claim is I 1. The combination with the cylinder in ternally enlar ed at various heights to form se arate iinnu ar recesses, of a plunger adapte to trap liquid in the lower portion of the cylinder and itself provided with passages permitting the trapped liquid to gradually escape to a recess above, said ')assages being arranged to be cut oil' in succession as the plunger descends. I

2. The combination with the cylinder having the internal annular recesses, of the hollow plunger having the recess in itsloweriacc and the erforations in its lateral walls; whereby liquid trapped by the plunger may escape gradually into the recess and plungercavity above and may return below the plunger as the latter rises.

3. The combination with a plunger-cylintier, of a plunger having an internal cavity and closely fitting and upwardly closing said cylinder, permanently, against influx to the space below the plunger, a fluid-chamber alongside the lower portion of the cylinder and communicating therewith, and an out weirdly-opening. check-valve normally closder internally enlarged to form annular recesses at dillerent heighten-car its lower end and provided with vertical interior grooves leading from tlie upper recess, ofa plunger fitting the interior of the cylinder, having a recess in its one lace, a central cavity above said recess, and provided with lateral perforations at different heights leadingto said rctress, andrwith other perforations inline with said groo vcs and leading to said cavit y, substantially as set forth. t

6. Thecombination with a plunger-cylin der having an upwardlytapered central block iixcd to bottom, of a plunger reciplocating in said cylinder, having a central internal chamber, and provided with an opening its lower wall to receive said tapered bloqlt the plunger descends, whereby the rising oi trapped liquid into said cavity is gradually stopped. I

7."l'hc combination with a plunger-cylmder provided with a side passage'lczuling to the open air, of a hollow plunger reciprocating in said cylinder and provided with a (when nel leading from the upper portion ofits interior, an outwardly-opening' valve controlling said cham'iel,'ai'id an outweirdly-opening valve controllingsaid passage, substantially as set tort h'.

Signed at her, 190%.

(,hicago this 2d day oi Decem- U. N. Manse. 

